System



2 Sheets-Sheet l.

(No Model.)

M. G.. FARMER.

ELECTRIC LIGHTING SYSTEM.

Patented JaII. 24,18 8 Z.

2 Sheets-Sheet 2.

(No Modem M. G. FARMER.

ELEGTRIG'LIGHTING SYSTEM. No. 252,886.v Patented Jani. 24,1882.

n. prima. Phew-ummm, wm'mgm, al;

, ed by the variations of the strength ot' current in the branch circuit, which correspondingly Vlamps of an electric-light system in branch or UNITED STATES PATENT OEErcE,

MOSES G, FARMER, OF NEITIOR'I, RHODE ISLAND.

ELECTRIC LIGHTING SYSTEM.

SPECIFICATION forming part of Letters Patent No. 252,836, dated January 24, 1882.

Application filed June 7, 1581.

To all 'whom it may concern Beit known that I, MOSES G. FARMER, a citizen ot the United States, residing at the United States naval torpedo station in the city and county ofNewport, and State of Rhode Island, have invented certain new and usel'ul Improvements in Electric Lighting Systems, as well as new and improved appa "atus thereto pertaining, of which improvements the following` is a specification.

My invention relates more particularly to the organization of the so-called incandescent system of electric lighting, or that in which a current of electricity is caused to traverse one or more sections of a conductor, which sections are composed of some suitable conducting inaterial refractory to heat, having a considerably higher resistance per unit of length than the remainder ot" the circuit` and by means ot' such resistance a portion of the electricity which traverses the circuit is converted into heat, which, when of sufficient intensity, produces light. These ends I attain by arranging the derived circuits, connected with the main line of conductors, and inserting in one of said branch circuits a device or apparatus regnlatcontrols a device or apparatus for regulating the strength of current traversing the main circuit. rIhe subject-matter claimed is hereinafter specilcally designated.

In the accompanying drawings, Figure l is a plan view ot' the apparatus. Fig. 2 is a theoretical diagram,illustratingthc electric circuits and the relation of the ditterent parts of the mechanism to each other; and Fig. 3 is a diagram graphically representing the law of dcvelopment of light by electric action.

In Figs. l and 2 of the drawings I have shown three electric lamps, L', L2, and Ijwhich are respectively placed in three separate branches of one electric circuit. It will be understood that the lamps need not necessarily be placed in the same position with reference to the regulator that they occupy in Fig. 1,but that they may be placed wherever their light is required, while the regulating mechanism may also be placed at any convenient point.

I will tirst describe the construction and mode (No model.)

ot' operation ot one of these lamps, and will afterwards explain the mechanism which I have devised for automatically maintaining a unif'orm strength in the electric current traversing them.

If a bar, wire, or strip of platinum, iridium, or other similar refractory substance, which is also a conductor of electricity, bc rendered iucandescent by the passage through it ofan electric current of sufficient power, a mild and pleasant light is emitted thereby, which is much less concentrated and glaring than that obtained in tl. e ordinary way from an arc formed between carbon pencils, and is also ot' more uniform brilliancy, provided the electric currentbe constantly maintained at a unilorm strength. Platinum-one ofthe mostrcfractory 1netals at't'ords alight equivalent to about one hundred candles per squareinch ot' incandescentsurfacc when within 2200 of its temperature of fusion, whileiridium,owingtoitshighermelting-point, produccsastill greater amountoflightunder the same conditions. In accordance with this priuciple I prefer to construct my electric lamp ot' a har or strip ot' one of the hereinbet'orementioned metals by aftixiug the same in an up right position between two metallic standards, I and P", hy means ot'suitable clamps, P and P2, as shown in Fig. 2, the electric current being made to pass through the said strip.

The quantity ot light which is emitted by an incandescent body at a high'temperature is proportionally much greater than that at a lower temperature. NVhen, therefore, heat is developed bythe passage of an electric current through a resisting-conductor, its temperaturc increases in a unich more rapid ratio than the increase in the strength ot' the current. Ihe ratio of the development or emission of light t'rom a platinum conductor, for example, is represented graphically in Fig. 3 of the drawings. It' the incre-ase iu the strength ot' thecurrenti'rom zero to a strength suiiicient to t'use the platinum conductor be observed at equidistant intervals, and the intensity or amount ot` light emitted at the several points of observation he measured, the ratio ot' the increase otl light will he represented with substantial accuracy hy the curved line in the ligure. It will be obvious from this diagram that the relative cost ot' producing a given IOO iight will. decrease rapidly as the absolute strength of current is augmented. Thus it requires only about twice the absolute strength of current to fuse a strip of platinum that it does to render it faintly luminous, and the amount of light emitted just below the temper ature of fusion is about tive times that which would be obtained with a current of sevencighths of the strength. While, therefore, a high temperature must be maintained in the incandescent lamp for the sake of economy, it is obvious that a slightvariation in the strength ofthe current at such a temperature will malte a very great ditference in the amount of light emitted. The object of my regulating apparatus therefore is to so regulate the strength ot' current as to secure economy, as well as uniformity, in the'light.

I will next explain the mechanism whereby a uniform current of any desired degree of strength is maintained in each lamp or series of lamps.

Oneof the main conductorsproceeding from the electric generator, which may be a dynamoelectric machine, a galvanic battery, or any other suitable source of electricity, is attached to the binding-screw G4, and the current proceeding from the generator passes from thence to the binding-screw G5, through an automatically-adjusted rheostat, to be hereinafter described, thence by the conductor c to the binding-screwC2, and thence by the conductor c, dividing atjj2j3 into three branches or derived circuits leading respectively1 to the three lamps L L2 L3. These branches again unite upon a single main conductor, o2, at the respective pointsjtjj, which main conductoris united at the binding-screw G with the return conductor leading back to the other pole ot' the electric generator.

The automatic regulator which is interposed in the main conductor-leadingfrom the source ot' electricity, and which is consequentlyY in that portion of the circuit which is common to all the branches and lamps in the system, may be constructed in various ways, the general principle being that any increase in the strength ot' the current shall simultaneously set in action mechanism causing a gradually-increasing resistance to be interposed in the circuit, while the opposite effect will take place when thestrength ofthe current is diminished. One very ettective arrangement which I have devised for this purpose is illustrated theoreti` cally in Fig. 2, and is also shown and described in detail in another division of this application, herein referred to. The principle of this apparatus will be sufliciently well understood by reference to the diagram Fig. 2 in connection with the following` description:

G is a cylinder or roller, constructed ot' nonconducting material and mounted upon a metallic support, D. G2 is another cylinder or roller, ot' metal, of similar size and form, mounted upon a metallic support, DT. A tlexihle conductor, R, of some metal offering considerable specic resistance to the passage of an electric current, has one of its ends connected with the axle and metallic support D8 of the non-conducting roller G, and is wound several times around the periphery of the said roller, (the convolutions being of course insulated from each other,) and thence passes across to the metallic roller G2 and a number of times around its periphery in the opposite direction. It being premised that one end of the tiexible conductor R is electrically connected with the binding-screw Gland the other with the .binding-screw U5, it will be readily understood that the rotation ol' both rollers G. and G2 in such a direction as to wind the conductor from one to the other, as indicated by the arrow, would have the effect of increasing the resistance of the circuit between the points C4 and C5, because the current is obliged to pass through such portion of the whole length of the conductor R as is not in contact with the metallic roller G2. Therefore the greater the portion of its length that is wound upon the insulating-roller G and otf from the metallic roller G2 the greater will be the resistance in circuit, and, conversely, the less it will become when the conductor is wound in the opposite direction. The required movement of the rollers G and G2 in one direction or the other is preferably effected by means ot' an independent motor, M5, the particular construction and arrangement of which are immaterial. Any known form of electro motor tot which the one shown in diagram in Fig. 2 is a type) will serve the purpose well. rlhe electric current for actuating such a motor may be derived from an independent source of electricity; or it may be taken from the main current, which supplies the lamps, by means of a branch or derived circuit, the former plan being usually preferable. The pinion P2 receives its motion from said motor, and is capable ot' being shifted in one direction or the other, so as to engage with one or the other ot' the toothed wheels, F F2, which are mounted upon the respective axles ofthe rollers G and G2. As the electro-motor M5, when in action, always revolves in the same direction, carrying with it the pinion P2, it is obvious that the rollers G and G2 will be caused to rotate in one direction or the other, according as the pinion PZ is engaged with one or the other ot' the toothed wheels F F2.

I will now explain the mechanism whereby the pinion P2 is shifted and the manner in which this shifting is automatically effected by the increase or decrease ot' the strength ot' the current in the main conductor.

Referring to Figs. l and 2, M represents a pairof electro-magnetic or magnetizinghelices, which are placed in one ot' the branch circuits uniting the poles ot' the generator.

m represents a pairot movable soft-iron cores, which tend to be drawn into helices when rendered magnetic by the action ot' the electric current, the distance which they are thus drawn depending upon the Astrength ot' the current.

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The movable cores m are attached to one end of a horizontal beam or lever, B, pivoted at or near its center upon a standard, F, the attractive force ot' the helices being opposed by the constant force of an adjustable antagonistic spring, 2. The lever B is capable of a slight vertical oscillation upon its axis, which is limited in each direction by adj ustable screwstopsfand I). One pole ot' a battery or other generator of electricity, X, is connected with the standard F by means of wire wf, which terminates in a binding post, C3. The adjustable contact-screw f is connected by the wire w2 with binding-post()7, and thence by Wire4 with an electro-magnet, M3. Similarly the contactscrew b is connected by the wire w3, bindingpost C6, and wire '105 with the electro-magnet M4. The electro-magnets M3 and M4 are connected by wires 107 and 10G, respectively, with a common binding-post, C8, to which the remaining pole of the generator is connected. This circuit may, if preferred, be supplied with electricity from the main circuit, which supplies the lamps, instead ot making use ot' a separate generator.

It will be understood, from the explanation which has been given, that as the lever B is de iiected from its normal p osition of equilibrium under the greater or less attraction exerted by the regulating-helices M in opposition to the constantforce ofthe spring2, an electric current will be directed through one or the other of the electro-magnets, M3 M4, as the case may be.

By reference to Fig. 2 it will readily be understood that the electromagnet M3, when in action, will by the force of its attraction throw the pinion P2 into gear with the wheel F', and in like mannerthe electro-magnet M4 will throw the pinion into gear with the wheel F2. Thus, if the current in the main conductor, and consequently that in the several branch conductors, tends to become too strong, the core m ot' the regulatinganagnet M will be attracted, causing the lever B to make contact with the point f, thus throwing the electro-magnet M3 into action, which shitts the pinion P2 in such a manner as to cause the motor M4 to interpose a gradually-inereasing resistance in the circuit, in the manner hereinbefore explained, and thus reduce the strength of the current traversing the regulating-helices M', as well as the several branch circuits and lamps, until the attraction in the magnet M becomes sufficiently diminished, when the antagonistic spring 2 will come into action and interrupt the contact atf, thus preventing further increase of the resistance. A decrease in the normal strength of the current will produce the reverse ett'ect upon the balanced lever B, and will also reverse the above-described mechanical operation, bringing the electro-inagnet M4 into action, and thus withdrawing the necessary amount of resistance from the main circuit. By this means the current traversing the entire system ot' main and branch circuits, which includes the lamp or lamps, will be automatically maintained at a practically-uniform strength, and this normal strength may be made greater or less at pleasure by varying the tension of the spring 2 or the position ot' the contact-stops fand b.

A regulator, in order that it may adequately control the operations of au extended system of lights, must not only be capable ot' maintaining a constant normal strength ofcurrent in each ofa definite number of branches, but it must also, without the necessity of readjustment, be capable of restoring said normal strength when by reason ot' the addition to the circuit of one or more branches the said strength tends to diminish, or when by reason of the withdrawal ot' one or more branches said strength tends to increase. The successful accomplishment of this end is a feature of the system herein described, in which, as has already been shown, the rheostat is placed in the main or common circuit, and is controlled by a governor operated by a branch current. This cannot be effected by any system in which the governing apparatus is located in the main circuit, for in that case the addition ot'an extrabranch would diminish thejoint resistance ot' the branches, thereby increasing the strength of currentin the main circuit, whilediminishing the strength in each branch, thus causing the governor to interpose additional resistance in the main circuit,\vhich would still furtherlessen the branch currents,instead of restoring them to their normal strength. 0a the other hand, let the governor be operated by a branch current, the addition ot' an extra brauch tends to diminish the current throughout the entire circuit, including that which traverses the branch in which the governor is located. The latter, by withdrawing resistance from the main circuit, operates to increase the current throughout the entire circuit until the normal strength in the governonbrauch is restored; but this is simultaneous with the restorationot' the normal strength in each ot' the lampbranches. In other words, the governor continually calls for the normal strength ot' current in its braneluand whatever be the number ot' branches, such normal strength is therein secured only upon the restoration ot' the normal strength in each ot'theremaining branches.

This application constitutes a division ot'one filed by me January 19, 1880, serial No. 965, which exhibits a convenient organization ot' apparatus for carrying out the objects of my invention.

l do not herein claim gradually varying the resistance of an electric-light circuit, nor the details ofthe regulating apparatus by which the same is etected, as these constitute the subjects-matter of other pending divisions ot' the above-mentionedapplication., Ido not, however, herein limit myself to the specific construction and organization of apparatus shown, as the details ot' such apparatus may be greatly varied without departing from the principle of my invention.

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It is advisable to include one or more electric lamps in the branch which contains the governing apparatus ot` the regulator, said lamps having conductors of similar electrical properties to those in the remaining branches. The object. of this is tlat a change may be effected in the specic resistance ofthe governing branch similar to those occurring` in the lamp-branches under the intiuence of a change in temperature.

I claim as of tny own inventionl. In an incandescent electric lighting system, the method hereinbetore dt cribed of uninterruptedly controlling the strength ot` current ot a main line ot' continuous conductors by and correlatively with incidental variations ot' strength in the same current traversing a continuous branch circuit.

2. In an incandescent electric lighting sys tem, the method hereinbefore described ot' varying the strength of current ot' a main line of continuous conductors by dynamic eft'ects produced by variations ot' strength in the same current traversing a continuous brauch circuit. 3. In an incandescent electric lighting sys tem, the method hereinbetore described of automatically controlling the strength ot' current traversing a main line ot' continuous conductors by and correlatively with incidental variations of strength in the same current traversing continuous branch circuits in which the lights are included.

4. The combination, substantially as set t'orth, of a generator of electricity, separate branches or derived circuits uniting the poles or main conductors thereof, mechanism for varying the strength of' the current tiowing through said conductors, means for controlling the currentvarying mechanistn included in one ot' the branches and actuated by the current tlowing therein, and an electric lamp or lamps included in each ot' the other branches.

5. The combination, substantially as hereinbefore set forth, ot a generator of electricity, two or more separate branches or derived circuits connecting the poles or main conductors of said generator, mechanism for regulating the strength ofthe electric currentin the main and branch circuits included in one ot' said brauch circuits and actuated by variations in the current traversing the same, and one or more electric lamps included in the remaining branch or branches.

6. The combination, substantially as herein bet'ore set forth, ot' a generator ot' electricity, two or more separate branches or derived circuits connecting the poles or main conductors ot` said generator, mechanism for regulating the strength ofthe electric current in the main and branch circuits, an electro-magnetic helix included in one ot' said branch circuits t'or con trolling said regulator, and one or more electric lamps included in the remaining branch or branches.

7. The combination, substantially as hereinbetere set forth, of a generator of electricity, tivo or more separate branches or derived circuits connecting the poles or main conductors of said generator, one or more electric lampsincluded in each ot' said branches, an adjustable rheostat included in that portion of the circuit ofthe generatorcommou to all thelamps` and mechanism, substantially such as described, whereby the resistance of said rheostat is diminished as the joint resistance ot' the whole number of lamps is increased, and the reverse.

In testimony 'whereotl I have hereunto set my hand this 4th day of June, 188i.

MOSES Gr. FARMER.

Witnesses:

Dames BAKER, HoWARD R. BUTLER. 

